visual restoration using focused ultrasound stimulation and immersive virtual reality after stroke

Conditions: Stroke; Visual Field Defect; Visual Field Defect Following Cerebrovascular Accident; Hemianopia; Quadrantanopia; Occipital Lobe Infarct; Visual Fields Hemianopsia

Summary: this research will explore if brain stimulation combined with virtual reality therapy improves visual impairment. the stimulation technique is called low-intensity focused ultrasound stimulation (lifus). the treatment uses ultrasound to stimulate vision specific parts of the brain. before this therapy, the participants will get structural brain imaging. functional brain imaging will be performed before and after the study's completion to measure brain activity response to therapy. the purpose of this research study is to evaluate patients who have had a stroke between 6 and 24 months ago with a visual field impairment. the duration of active participation in the study is 1.5 months.

randomization visit and 1st intervention visit: the randomization visit and 1st intervention vision will be on the same day. participants will be "randomized" into one of the study groups described below. * group 1 (sham group): inactive lifu + vr * group 2 (active group): lifu + vr neither the subject nor the researcher conducting this study will know which group participants are in. sham lifu: the setup is similar for the active stimulation group, except that a high acoustic impedance disk will be placed between the lifu probe and the scalp that mimics the audible sensation of a slight buzzing but attenuates more than 95% of the energy into the brain. the audible sound is nearly identical for both the sham and active stimulation. intervention visits (9 sessions over 21 days, about 2.5 hours per visit): at these visits, participants will undergo the investigational study interventions. there will be 30 minutes of a vr session and 20 minutes of active lifu or inactive lifu treatments.

Eligibility criteria:
inclusion criteria: * ≥ 18 years old of any gender and race * clinical ischemic stroke or hemorrhagic (confirmed by ct or mri) that occurred \>= 6-24 months ago * partial or complete homonymous hemianopsia on clinical exam exclusion criteria: * documented history of severe dementia with or without medication before stroke that affect subject's ability to participate in and be compliant to study protocol * significant upper motor deficits and the subject cannot do ivr sessions at the baseline * history of seizures * inability to get a new mri * presence of any ultrasonic stimulation risk factors: an electrically, magnetically, or mechanically activated metal or nonmetal implant including cardiac pacemaker, intracerebral vascular clips, or any other electrically sensitive support system; non-fixed metal in any part of the body; pregnancy (the effect of ultrasonic stimulation on the fetus is unknown); preexisting scalp lesion or wound or bone defect or hemicraniectomy. * patients will be excluded if they have a previous diagnosis of hemianopsia, a new diagnosis of central retinal ischemic injury, or visual blindness or a history of any other ocular disease. * concerns about the inability to complete study visits/procedures by the pi.

Keywords: virtual reality stroke visual deficit chronic stroke ultrasound stimulation neuromodulation stroke recovery visual field defect funcational imaging